In a contemporary display apparatus such as a television receiver, a set of external controls such as keys or dials is typically provided on a remote control device or on the television receiver itself as a user interface device for manually setting corresponding display characteristics of a screen of the television receiver. Such a user interface device provides the user with means to adjust as desired a variety of display characteristics, for example, contrast, brightness, color density, tint, sharpness, and backlight. In other words, a user manually controls a display characteristic of a contemporary television receiver by manipulating the corresponding external control.
These display characteristics are subjective parameters best set according to user preferences, but they are particularly affected by the current ambient conditions in the vicinity of the screen with respect to the television receiver's installation site. That is, the ambient conditions directly affect the display characteristics, and the most significant ambient condition is luminous intensity, which can be measured as luminous flux (lux) incident on a unit area, where one lux (lx) of illuminance equals one lumen per square meter (1 m/m2).
For example, in cases where the level (intensity) of ambient illuminance is high or low, a brightness display characteristic of a screen should be set accordingly. Other display characteristics are likewise manually adjusted according to user preference, such that performance of an individual adjustment of each display characteristic is necessary for varying ambient luminosities, which inconveniences the user. At the same time, the status of the settings of such display characteristic may be unknown to the user at any given time, further encumbering accurate adjustments.